JPH04299800A - Microwave apparatus for preventing collision between vehicles and data transmitting method therefor - Google Patents

Abstract

PURPOSE: To provide an electronic device which automatically makes a mutual communication between plural automobiles by sending an alarm to specially a driver which has the possibility of danger and further automatically sending out a signal used to evade a collision. CONSTITUTION: This is a method for transmitting data between moving bodies like automobiles and a transmitter and a receiver which have a communication by radio are fitted to the vehicles 10, 11, and 23 respectively; and the transmitter of the 1st vehicle sends encoded data regarding the action of the 1st vehicle to the receives of other vehicles and the receives of other vehicles have devices which process encoded data used by the drivers of the vehicles. The data are transmitted in two pulse forms with microwaves and one pulse has a modulation frequency FMF and travels to in front of the vehicle while the other pulse has a modulation frequency FMR and travels to behind the vehicle, but the two frequencies FMF and FMR are different and a function of a modulation frequency FM.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the range of motor vehicle driving accessories. More particularly, the present invention relates to electronic devices for automatic communication between vehicles, which automatically transmit specially adapted signals to alert potentially dangerous drivers and prevent collisions.

0002

BACKGROUND OF THE INVENTION The need for anti-collision systems for vehicles, particularly automobiles, trucks, and buses, increases as traffic volumes increase. This need has been explained, for example, by car manufacturers, who have announced some plans for improving highway safety and improving driving aids, such as most European manufacturers. The Prometheus Drive Project (the
PROMETHEUS and DRIVE prog
rams) is being developed.

Although the purpose of these plans is to provide a complete collision avoidance system, these systems do not alert drivers to the risk of a collision and to take avoidance measures such as braking or turning. It's the type that warns you on the hand.

There are several types of collision prevention devices employed in automobiles, and these devices create an image of the vehicle's situation from data obtained by sensing devices. These detection devices are usually radars operating at high frequencies or using lasers (transmitting and receiving lasers) called lidars. The created image of the vehicle's situation is generally judged by an on-board computer and instantly determines the degree of risk of collision. This data can be in any suitable form (audible signal,
The driver is notified by light, voice synthesis, etc.).

[0005] With such a device, in particular, the driver can receive a warning that the driver is not maintaining a safe distance from the vehicle in front, or can be made aware of the dangerous behavior of other drivers.

[0006]

[Problem to be Solved by the Invention] Various articles or documents, particularly the Institute of Transportation,
Transportation:I. R. T) to 1
“Detection” released in October 1984
d'obstacles and prevention
de collisions entre Vehi
According to this document, the disadvantage of these devices is that they do not provide a sufficiently wide image of the situation (the width of the radar or reader antenna is only 1°). ), a sufficiently wide image of the situation may not be obtained, especially if natural or artificial occlusions affect the propagation and limit the size of the received image and therefore the splitting of the hazard. Screening areas are created, and these screenings are also caused by plants, curves or metal surfaces such as road signs or safety obstacles.

Furthermore, the reader cannot be used in rain or fog because water molecules diverge the propagating light rays. Only electromagnetic radar can be used even in poor weather conditions. These devices can generate false alarms, especially if the sensor is defective.

In other respects, the criteria used to determine the risk of false alarms are complex and often result in false alarms. The complexity of these criteria is due in large part to the fact that the radar or reader generates a large amount of data, and among other things, it must classify the received data and then calculate the speed of the object and the probability of a collision. This is due to necessity.

Document DE-A 2.559.184 describes a wireless alarm system which obviates some of the aforementioned drawbacks. The described system provides for transmitting encoded data relating to initial vehicle movements in the form of a frequency modulated HF carrier wave with a modulation frequency specific to the data being transmitted. Such transmission provides the system with reliability regardless of weather conditions.

However, a drawback of this system is that, like conventional systems, it is not possible to discern the direction of the transmitting vehicle's location relative to the receiving vehicle.

Another disadvantage of conventional devices is that these devices have a fairly short coverage area due to the low power available. Moreover, this power cannot be increased very much due to power consumption and cost reasons.

0012

SUMMARY OF THE INVENTION The object of the invention is inter alia to overcome these drawbacks.

More particularly, one of the objects of the invention is to provide a device for preventing collisions between vehicles by providing a much smaller shielding area than is the case with radars and readers.

Another object of the invention is to provide a reliable device for determining the level of danger using a simple and non-false alarm decision algorithm.

A complementary object of the present invention is to provide a low power consumption device with wide coverage and improved safety.

[0016] These objects are obtained by a method for transmitting data between movements, as stated in claims 1 to 7, as will be seen later.

Each transmitted data corresponds to the following groups of information: data for deceleration or braking; overtaking data; stopping data.

The encoded data is transmitted in the form of three consecutive pulses, the first of which is a frequency modulation FM pulse corresponding to the carrier frequency F1 and the transmitted data. , the second pulse has a carrier frequency F2 different from F1 and is frequency modulated by FMF, and the third pulse has a carrier frequency F2 which is frequency modulated by FMR.

The presence of a pulse with a first carrier frequency F1 that is different from the carrier frequency F2 of the other two pulses allows the receiver to estimate the distance to the transmitter.

The distance estimation determines the level of danger and at the same time cancels the consideration of data sent by vehicles at a distance greater than the safe distance, which data is a function of the speed of the receiving vehicle. .

Advantageously, said pulses corresponding to the transmission of data for deceleration or braking are sent at a frequency of repetitive pulses proportional to the deceleration of said vehicle, and data for overtaking and stopping are transmitted at a constant repetition frequency. Ru.

It is clear that the braking ratio of the vehicle is important as described below.

The invention furthermore relates to a device for the prevention of collisions between vehicles using a method of the above-mentioned type, which device is set out in claims 8 to 17.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail below with reference to the drawings, but the invention is not limited to these embodiments.

FIG. 1 shows two vehicles, one running behind the other, both of which are equipped with the device according to the invention.

The data transmitted between vehicles relates to several actions taken by the driver. The principle of the invention on which this application is based is that stop lights and indicators are used in particular to avoid collisions between vehicles. However, these stop lights are only visible in good weather and have little effect in the case of fog, downpour or bright sunlight, or even the blinding light of an approaching vehicle. Furthermore, the driver can only see the stop lights or turn signals of the vehicle immediately ahead. Due to these constraints,
The disturbances that occur when many vehicles are in succession add to the driver's reaction time.

In order to solve this drawback, a method is known in which HF transmission is used to communicate stop or deceleration data.

[0028] The transmitted data is standardized in order to facilitate the analysis of these data and the reconstruction of the received data and to determine the level of danger.

The present invention utilizes the transmission of microwaves to transmit data in such a way that the receiving vehicle can know whether the vehicle emitting the microwaves is moving in the same direction or in the opposite direction. It includes doing.

In FIG. 1, there is a vehicle 11 after the vehicle 10.
Two vehicles 10 and 11 are each equipped with a device according to the invention.

Receiving antennas 12, 13 and transmitting antennas 14, 15 are attached to vehicles 10 and 11, respectively. The transmitting antennas 14 and 15 are fixed to the tips of the whip antennas of the vehicles 10 and 11, and data can be transmitted over long distances by preventing microwaves from being disturbed by vehicles of the same category (same height) that interfere with this transmission. It is convenient to do so. Advantageously, the receiving antenna is mounted on the vehicle in such a way that it can only receive data coming from the vehicle in front. In this way, reception of data coming from behind the vehicle is avoided. The receiving antenna of the vehicle 10 therefore does not receive data transmitted from the transmitting antenna 15 of the vehicle 11. On the other hand, the receiving antenna 13 of the vehicle 11 can receive data transmitted from the transmitting antenna 14 of the vehicle 10.

The receiving antennas 12, 13 are advantageously reflector antennas with horizontally wide-angle beams and vertically narrow-angle beams. According to a preferred embodiment, the coverage area of the receiving antennas 12, 13 is 20° horizontally.
and 10° in the vertical direction, and the theoretical gain of these antennas is 300.

The transmission of data between vehicles according to the features of the invention takes place in the millimeter band, for example 60 GHz, and the microwaves are absorbed over a certain distance.

FIG. 2 shows three vehicles, each equipped with a device according to the invention, one of the vehicles approaching the other two.

There is a vehicle 11 behind the vehicle 10, and this vehicle 10 passes a vehicle 20 coming from the opposite direction. Vehicle 1
The receive beams of 0, 11, and 20 are 21, 23, and 2, respectively.
4. The data transmitted by vehicles 10 and 20 is supplemented by vehicles in their vicinity. Thus, in the illustrated situation, vehicle 11 receives data from vehicles 10 and 20. These data relate in particular to the stop lights and turn signals of vehicles 10 and 20.

According to a preferred embodiment, the data transmitted by the device of the invention are: data for deceleration or braking; overtaking data; stopping data;

The stop or deceleration data alerts the driver of decelerations of vehicles ahead but hidden by other vehicles or natural or man-made obstacles. It is also possible to predict vehicles that are braking. This eliminates, among other things, the accumulation of driver reaction time and many vehicle collisions. Conveniently, such data is sampled from a brake switch controlling a stop light, or directly from a speedometer. Overtaking data comes, for example, from the vehicle's turn signal relay. When receiving such data, a driver may or may not think that he or she is on a wide freeway, a four-lane highway, or a two- or three-lane highway. . Data indicating whether the vehicle is stationary allows the driver to know if the vehicle is braking, in a traffic jam, or in a traffic accident. These data can be obtained, for example, from flashing warning lights when the vehicle is stopped.

On the other hand, when the vehicle 11 is receiving overtaking data, it is necessary to know whether these data are from a vehicle coming from the opposite direction (vehicle 20) or from a vehicle in the same direction (vehicle 10). is important. When receiving any danger signals, it is equally essential to know that these data come from vehicles either inside or outside the required safety distance.

FIG. 3 is a block diagram of a data transmitting device according to one embodiment of the present invention. The transmitting device 32 is also called an emitter, and it receives signals 35, 36, 3 as input.
There is a modulation generator 30 that receives 7. Signal 35 is the signal coming from the vehicle's left turn indicator relay with a transmitter. This signal 35 is present when the driver uses this left turn signal to pass another vehicle or turn left. Signal 36 corresponds to a flashing warning light obtained from the direction relay. Signal 37 is a signal for deceleration, speed, or brake data. When receiving any of these three types of signals, the modulation generator 30 sends one signal to a pulse generator 31, for example a pulse modulator, and sends one frequency control signal to a transmitter 33 of the modulated carrier frequency. Further, based on the basic feature of the present invention, an antenna lobe switching command is sent to the phase switch 34 of the antenna power supply circuit.

More specifically, data from the left turn indicator and stop light is transmitted by transmitting antennas 38 and 39 to nearby vehicles.

According to the invention, data is transmitted for a very short time in instantaneous windows corresponding to the appropriate times of the pulses generated by the pulse modulator 31.

[0042] If the vehicle transmitting data is decelerating, pulses with a repetition rate proportional to the deceleration are sent out at a certain constant frequency. The occupancy ratio, which corresponds to the ratio of effective delivery time to total delivery time, is usually low to limit interference in the case of several vehicles. The occupancy rate can also be expressed as a percentage of the transmission time. A low occupancy rate indicates that the transmission time is very short or that the blank time is sufficiently large. This ratio is used to avoid occupying the receive antenna for long periods of time, as shown below.

[0043] When a driver uses a turn signal to overtake, that is, when the driving direction is on the left, when the driver turns to the left,
The transmitter sends out a series of pulses at a modulation frequency different from the brake frequency. The carrier frequency is determined by the modulation generator 30
is generated by the module 33 according to the command.

The use of a flashing alarm indicator transmits a series of frequency modulated pulses that are different from the frequency modulated pulses for the rotation and braking indicators. According to an embodiment of the invention, the frequency modulation FM of the microwave signal generated by the generator 30 has the following frequencies: (1) FM for braking = 50 MHz, with a repetition frequency of 0 to 10;
(2) FM for direction indicator = 60MHz, repetition frequency is 50Hz.
(3) FM=0Hz for flashing warning light
At 40 MHz, the repetition frequency is 500 Hz.

A repetition frequency of 500 Hz means that a signal occurs every 1/500 of a second.

Regarding the direction of traffic, the present invention uses dual transmitting antennas 38, It is proposed to use 39.

Physically, antennas 38 and 39 are made on the same very small substrate and can be easily attached to the tip of a vehicle's radio antenna.

Technically, the antennas 38, 39 have a network of two radiating dipoles spatially separated by λ/4;
The receiver can distinguish between data coming from vehicles moving in the same direction and data coming from vehicles moving in the opposite direction. These circuitry can be printed on a radio-electrically transparent dielectric medium, for example.

More specifically, the phase switch 3 is controlled by the antenna lobe switching command coming from the modulation generator 30.
4 switches the relative phase of one antenna to each other. The phase switch 34 includes two phase switching units 54, 5.
There are 5. Units 54 and 55 send signals phase-shifted by π/2, 0, and −π/2 to antennas 38 and 39 according to commands from modulation generator 30.

FIG. 7 shows the antenna pattern of the phase switch produced by the module 34 in a known manner. Due to the three phase differences, a lobe 71 directed toward the front, a lobe 72 directed toward the rear, and double lobes 73 and 74 directed toward the front and rear of the vehicle 70 at the same time are obtained. This action and function can be better understood in Figures 5A, 5B, and 5C.

FIGS. 5A, 5B and 5C show the signals emitted by a vehicle equipped with the device according to the invention, the signals received by the vehicle viewed from the rear, and the signals received by the vehicle viewed from the front, respectively.

The repetitive data sent out by the apparatus of FIG. 3 is shown in FIG. 5A. This repetition may be performed, for example, by three repeated pulses 50, 51, 5, all in the same direction and of the same magnitude.
It is composed of 2.

[0053] The first sending pulse 50 is, for example, 60 GH.
It consists of a microwave signal F1 of z, and by the transmitted data (
Brake, direction change, stop) frequency FM = 40, 50,
Or it is modulated with a 60MHz signal. This pulse contains a 60 GHz carrier wave and serves as a reference for the signals contained in pulses 51 and 52, which are simultaneously transmitted from the front and rear of the vehicle through two transmitting antennas. It will later be seen that this first pulse only serves to estimate the distance.

Immediately after pulse 50, a pulse 51 is transmitted, which has a carrier frequency F2 different from F1.
There is a frequency modulation FMF (FM front) which shows the function of FM. During the transmission of this pulse, the maximum gain lobe of the antenna is switched to the front of the vehicle.

A pulse 52 with a carrier frequency F2 and a modulation frequency FMR (FM rear) which is different from FM and is a function of FM is formed after pulse 51. The direction of the maximum gain lobe is toward the rear of the vehicle.

According to the present invention, the modulation frequencies FMF and F
The values of MR are as follows: FMF=FM-10MHz FMR=FM+10MHz Here, FM takes different values depending on the data to be transmitted.

First carrier reference pulse F different from F2
1, advantageously separate emitters and receivers are defined as described below.

The shape of the pulses received by the vehicle seen from the rear is as shown in FIG. 5B, and there is a second pulse with a smaller amplitude than the third pulse, which is the same as when pulse 51 was sent. This is because the direction of the maximum gain lobe of the antenna is toward the front of the vehicle.

The shape of the pulses received by the vehicle viewed from the front is as shown in FIG. 5C, and there is a pulse with a second amplitude larger than the third pulse.

Amplitude modulation of the received signal is obtained from the successive transmission of two pulses containing data (FM), one of the two pulses being sent forward and the other backward; indicates whether the transmitting vehicle is being viewed from the front or from the rear, as described below.

FIG. 4 shows a receiver 49 based on an implementation of the invention.
FIG.

[0062] The receiving antenna 40 receives signals transmitted from other vehicles. The received signal consists of frequency and amplitude modulated signals. Local oscillator 42 for mixer
Signals from the are also input. The signal output from mixer 41 has an intermediate frequency and is amplified by amplifier 46. The signal from amplifier 46 is input to frequency discriminator 43 and amplitude measurement module 44 . The frequency discriminator 43 is the amplifier 4
Measure the frequency of the signal coming from 6. The amplitude measurement module 44 measures the amplitude of the intermediate frequency signal.
This signal determines the location of the transmitter, and further data received when the transmitting vehicle is beyond a safe distance is ignored. Frequency discriminator 43 and amplitude measurement module 44 send data to module 45, which
5 includes a detection and front/rear identification device and a device for calculating the distance and braking rate of the transmitting vehicle. These data are selected and passed through anti-echo devices 53 which suppress or do not process the received signals for reasons explained below. The anti-echo device includes, for example, two switches, the positions of which are controlled by module 45.

Forward/backward discrimination is based on the amplitude modulation of the two received pulses, the modulation frequencies of which are FMF and FMR, respectively. The detection and forward/backward discrimination device of module 45 uses the frequency and amplitude data sent from frequency discriminator 43 and amplitude measurement module 44, respectively, to compare the amplitudes of these two pulses.

If the amplitude of the pulse FMF is smaller than the amplitude of the pulse FMR, the case shown in FIG. 5B is obtained, in which case the danger situation (the transmitted danger signal) comes from a vehicle moving in the same direction as the receiving vehicle. The opposite case is that of FIG. 5C, where the transmitting and receiving vehicles are facing each other and passing each other.

Module 45 sends an order to local oscillator 42 to switch to the carrier frequency (F1/F2) so that the signal entering amplifier 46 is an intermediate frequency signal. The device of module 45 further includes output interface 4
7, this output interface 47 sends a message 48 to the anti-collision unit or to a display making the information visible to the driver. The data is further transmitted to the driver by a speech synthesizer.

The output interface 47 can also act directly, for example to apply the brakes, if the danger level is very high. This means that the driver's reaction time, which is typically on the order of 1 to 2 seconds, can be shortened.

It can be seen that the receiver 49 is thus able to reproduce data regarding the environment of the vehicle, in particular braking, overtaking, the position of the vehicle (front or rear), and the distance of the transmitting vehicle.

[0068] If one vehicle makes several transmissions at the same time, it is advantageous to assign priorities to the received information. For example, a blinking alarm can be given a higher priority than a brake, and a brake can be given a higher priority than an indicator.

The roughly estimated distance of the transmitting vehicle is determined using characteristics of the transmission environment. FIG. 6 shows atmospheric absorption curves for data transmission frequencies.

Distance estimation is necessary to evaluate data received from vehicles outside the stable range. This distance can be fixed in advance. According to a preferred embodiment of the invention, the safety distance depends on the speed of the vehicle.

As already pointed out, distance calculations are carried out by a distance calculation device integrated in module 45;
The characteristics of the transmission environment for 0 GHz are utilized. This curve is shown in FIG.

[0072] The distance evaluation uses the ratio of the amplitudes of the signals with frequencies F1 and F2, but these signals are between the two, that is, between the first pulse and one of the other two pulses. The difference between F1 and F2 is sufficient for differential absorption effects and can be measured at a safe distance.

The presence of the first pulse at carrier frequency F1 is not necessary for forward/backward discrimination, but is essential when it is desired to evaluate the distance between the transmitting side and the receiving side.

FIG. 6 includes two curves 60 and 61.

Curve 60 shows atmospheric absorption at sea level (altitude=0 m), and curve 61 shows atmospheric absorption at 4000 m altitude.

The following table shows the situation obtained from the two curves.

[0077] For curve 60, the carrier frequency is 60 GHz.
The atmospheric absorption of is 15 dB/m, but it is 1 dB/Km when the carrier frequency is 65 GHz. In this invention, the distance of the transmitting vehicle is estimated using the amount of attenuation of carrier waves of various frequencies.

According to this preferred embodiment, F1
=65GHz and F2=60GHz are selected. 300m
For a safe distance of , there is a 3 dB difference between F1 and F2 at normal atmospheric pressure.

In addition, the receiving device can be equipped with a pressure sensor, which allows a distance correction, which depends on the frequency attenuation of the oxygen line (approximately 60 GHz) as a function of pressure and therefore altitude. This is done by measuring the amount.

Other carrier frequencies can also be used to make a difference between the two frequencies and allow the distance between the transmitting and receiving vehicles to be determined (eg F2=90
Attenuation is only 0.1dB/Km for GHz)
.

Another feature of the invention is that the receiving module is fitted with an echo prevention device (module 53, FIG. 4). This device can prevent the reflection of microwaves from vehicles or objects that are behind the vehicle transmitting data and facing toward the receiver. You get the impression that it is coming from behind the vehicle behind you.

Immediately after receiving the third pulse in the series, the echo prevention device is activated for a fixed period of time, eg 0.5 μm.
s. Prevent the reception or processing of microwaves.

Furthermore, when a vehicle brakes on a bridge on the road, the signal received by the vehicle on the road does not have the modulation necessary for consideration, but this is because the amplitude modulation is, as shown in FIG. This is because forward transmission lobes and rearward transmission lobes are symmetrical with respect to ZZ' which is perpendicular to the traffic direction XX' of the vehicle 70, and therefore cannot occur between FMF and FMR.

According to the present invention, 1 for the carrier frequency
An accuracy on the order of 1/000 is sufficient, and the pulse width is 0.2 μs for a peak power of 1000 mW.

The stability of the frequency of the local oscillator of the receiver is also 1.
It has a passband width of 200 MHz with respect to F1.

The bandwidth of the frequency and amplitude modulator is 5MH
z and is adapted to the discrimination of pulse widths and different modulation frequencies.

The transmitting antenna is made up of two networks of antennas with a beam width of 35° and a gain of 50 without calculating the directivity and auxiliary gain due to the relative phase effect of the two networks.

[0088] The receiving antenna can be designed to have a cosecant so that it can receive signals that do not normally fall within the receiving lobe.

The invention is not limited to vehicles such as buses, trucks, and motorcycles, but can be applied to ships and more general moving objects.

[Brief explanation of drawings]

1 shows two cars being driven, one behind the other, both cars being equipped with a device according to the invention; FIG.

2 shows three vehicles equipped with the device according to the invention, one of which faces the other two following; FIG.

FIG. 3 shows a block diagram of a device or transmitter for data transmission according to an embodiment of the invention;

FIG. 4 shows a block diagram of a device or receiver for data reception according to an embodiment of the invention.

FIG. 5A shows a signal transmitted from a vehicle equipped with a device according to the invention;

FIG. 5B shows signals received from a vehicle seen from the front.

FIG. 5C shows signals received from a vehicle viewed from the rear.

FIG. 6 shows an atmospheric absorption curve near the data transmission frequency.

Figure 7 shows forward and backward transmit lobes

[Explanation of symbols]

10, 11, 20, 70 Vehicle 12, 13, 40 Receiving antenna 14, 15, 38, 39 Transmitting antenna 21, 23,
24 Receive beam 30 Modulation generator 31 Pulse modulator 32 Emitter 33 Transmitter 34 Phase switch 35, 36, 37 Input signal 41 Mixer 42 Local oscillator 43 Frequency discriminator 44 Amplitude measurement module 45 Includes detection and forward/backward discriminator Module 46 Amplifier 47 Output interface 48 Message 49 Receiver 50 First transmitted pulse 51 Second transmitted pulse 52 Third transmitted pulse 53 Echo prevention device 54, 55 Phase switching unit 71, 72, 73, 74 Lobe

Claims (17)

[Claims] Claim 1: A method for transmitting data between a plurality of mobile bodies, each mobile body being equipped with a transmitter and a receiver capable of wirelessly exchanging individual data;
The transmitter of the second vehicle transmits to the receiver of the other vehicle encoded data defining the behavior of the first vehicle in the form of a carrier wave frequency modulated at a modulation frequency FM specific to the data being transmitted. However, the frequency of this carrier wave is microwave, and the data is transmitted to the front and rear of the first vehicle with two different modulation frequencies FMF and FMR that are a function of the unique modulation frequency FM. transmitted in the form of pulses, characterized in that the reception consists of: (1
) from FMF and FMR to the data-specific frequency F
Retrieving M; (2) Distinguishing data sent by moving objects moving in opposite directions from data sent by moving objects moving in the same direction by comparing the amplitudes of the two pulses. 2. The encoded data is transmitted in the form of three consecutive pulses, the first pulse of carrier frequency F1 and the modulation frequency FM corresponding to the transmitted data; pulses are transmitted forward and backward at the same time, and the second pulse at carrier frequency F2 is different from F1 with respect to modulation frequency FMF, and the third pulse at carrier frequency F2 is different from modulation frequency FMR. A method according to claim 1, characterized in that: 3. The modulation frequency FMF is smaller than the modulation frequency FM, and the modulation frequency FMR is lower than the modulation frequency FM.
Method according to any one of the preceding claims, characterized in that FM is greater than the modulation frequency FM. 4. The method according to claim 3, characterized in that, when FO is a predetermined frequency, the following relationships are used: FMF=FM-FO FMR=FM+FO. 5. A method according to claim 1, characterized in that each of the transmitted data corresponds to the following types of data: (1) slowing down; Or brake data (2) overtaking data (3) stopping data. 6. Pulses corresponding to the transmission of data for damping or braking are transmitted at a repetition frequency proportional to the deceleration of the first vehicle, and further pulses corresponding to transmission of overtaking and stopping data are transmitted at a fixed repetition frequency. 6. The method according to claim 5, wherein the method is transmitted at: 7. On the receiving side, the distance between the first transmitting vehicle and the receiving vehicle is determined by the ratio between the amplitude of the first pulse and any one of the other two pulses. 7. The method according to claim 2, wherein the method is determined by calculating . 8. A device for preventing collisions between moving bodies of the type using the method according to any one of claims 1 to 7, characterized in that it consists of: (
1) A device for transmitting data in the form of one pulse to the front of the vehicle and one pulse to the rear of the first transmission vehicle with different modulation frequencies, and the modulation frequencies are FMF and FMR, respectively. , which are a function of the data's characteristic modulation frequency FM, which in turn is a modulation of a single microwave carrier frequency F2; (2)
A device for receiving data from the first vehicle, the modules included in this device include a detection and front/rear identification device, which compares the amplitudes of the received pulses and further identifies the first vehicle. It is used to distinguish between data coming from a vehicle moving in the same direction as the vehicle and data coming from a vehicle moving in the opposite direction. 9. A device according to claim 8, characterized in that the device for transmitting data comprises: (1) generating pulses in the form of a frequency modulated microwave carrier wave; (2) A modulation generator for controlling the device for generating the pulses, which modulates the frequency of the carrier wave and the pulse depending on whether the pulses are transmitted forward or backward. (3) A phase switch connected to the transmitting antenna and controlled by the modulation generator according to whether the transmission is forward or backward. 10. Device according to claim 9, characterized in that the transmitting antenna consists of a network of two dipoles mounted on one substrate. 11. The apparatus according to claim 9, wherein the transmitting antenna is fixed to the tip of a whip antenna attached to the moving body. 12. The device for transmitting data is configured to transmit forward and backward transmitted pulses with FMF and FMR modulation frequencies, respectively.
A modulation frequency F that modulates a carrier wave with a frequency F1 different from 2.
12. Device according to any of claims 8 to 11, characterized in that it transmits M first pulses. 13. Apparatus for receiving said data includes a frequency discriminator for measuring the frequency of the received pulses and a module for measuring the amplitude of said pulses, these measurements being equal to said data. 8 to 1, characterized in that data coming from a vehicle moving in the same direction as the first vehicle and data coming from a vehicle moving in the opposite direction are identified.
2. The device according to any one of 2. 14. The device for transmitting data further comprises a device for calculating a distance between a receiver of the first vehicle and a transmitter of a vehicle in its vicinity; 13. Apparatus according to claim 12, characterized in that the calculation is performed from the ratio of the amplitude of the first pulse and the amplitude of any of the other two pulses. 15. Device according to claim 8, characterized in that the device for receiving data comprises an anti-echo device used to stop the received signal. . 16. The device for receiving data comprises an output interface used to signal the driver of the first vehicle to receive traffic situation data. Apparatus according to any one of claims 8 to 15. 17. The device for receiving data includes a receiving antenna for receiving the transmitted data, and the receiving antenna is located at a position where the first vehicle receives only data coming from in front of the first vehicle. 17. A device according to any one of claims 8 to 16, characterized in that: